Method of die casting separable fasteners



May 34 i940 L. H. MORIN ET AL METHOD OF DIE CASTING SEPARABLE FASTENERSFiled March 17, 1938 Patented May 1.4, 1940 UNITED STATES PATENT -OFFICEMETHOD OF DIE CASTING SEPARABLE FASTENERS Application March i7, 1938,Serial No. 196,353-

4 Claims.

rIhis invention relates to the die casting of the links of separablefastener stringers, either by the use of metal alloys or thermoplasticmaterials. More particularly, the invention relates to a @method whichconsists in casting two or dual links in a single casting operation upontwo Stringer tapes arranged in close proximity to each other so as toproduce in a single successive series of casting operations twostringei's of a yseparable fastener, and then in severing the two ordual links to form the two stringers of a separable fastener. The novelfeatures of the invention will be best understood from the followingdescription and annexed drawing in which the several parts aredesignated by suitable rei'- erence characters in each of the views, andin which:

Fig. 1 is a diagrammatic sectional View through a die illustrating amethod of forming two united -.-,die cast links upon two tapes arrangedin close proximity to each other.

Fig. 2 is a view similar to Fig. 1 showing the die parts in spacedrelation to each other in separating the formed casting therefrom.

Fig. 3 is a sectional View at right angles to that shown in Fig. 2illustrating the dies partially closed and demons-trating the operationof stripping the core pins from the castings, the 'section beingsubstantially on the line 3-3 of Fig. 1.

Fig. 4 is a face View of a portion of two Stringer f strips with thedual links arranged on adjacent edges thereof.

Fig. 5 is a sectional view diagrammatically i1- lustrating the method ofsevering the unit as seen in Fig. 4 in forming the separate stringers,each having a series of links or scoops thereon, and

Fig. 6 is a sectional plan view similar to Fig. l yshowing the dies infull line and illustrating the nozzle in a diierent position.`

In Figs. 1 to 5 inclusive we have shown one method of carrying ourinvention into eiiect. In Figs. l to 3 inclusive, we have shown tworelatively movable die parts I and II having a parting line as at I2. AtI3 is shown an impression formed between adjacent surfaces of the dieparts I and II at the parting line I2 thereof. This impressionis of suchcontour and size as to form a single die cast body III, each sideportion of which will form, when this body is cut or severed centrallythereof, two links or scoops I Ia which will be arranged upon separateStringer tapes I6, I 6a which are supported between the dies I0 and II.'Ihe beaded or enterial from `one or more cylinders.

larged edges Il, I'Ia of the Stringer tapes IS, Ilia are disposed Withinthe impression I3 so that the body I4 is cast thereon as will be apparent.

Arranged on the parting line I2 of the dies 5 and movable at rightangles to the movement of said dies toward and from each other are twosimilar core pins one of which is shown at I8 in Fig. 3 of the drawing.The inner ends of these core pins form recesses I9, Isa on one sur- 10face of the body Iii adjacent the central portion thereof, so that whenthe body is severed, the recess I9 will be on the link I5 and the recessIda on the link la. The opposite surface of the body I4 has formedthereon projections 2B, 20a in' alinement with the recesses I9, I9a soas to register with the recesses of an opposed Stringer in coupling twoStringer tapes together, as in other fastener devices of this kind. Theprojections 26, Za are formed by crevices or recesses 2l, 2id formed inthe die parts III and II, as will be apparent from a consideration ofFigs. 2 and 3 of the drawing.

In the construction shown the die It is provided with an admissionopening or gate passage '22 with which an injection nozzle 23 registersin pressure feeding or injecting suitable casting material into theimpression or mold cavity IS of the dies in forming the casting. It willbe understood that suitable metals or metal alloys may be used in makingthe castings. On the other hand, suitable thermoplastic materials may beemployed. In connection with'the latter we may use the teachings setforth in our prior applications Serial Nos. 131,606, 131,607 and 131,-608, all filed March 18, 1937, especially from the standpoint of usingdual or independent cylinders which may be brought into registeringposition with the passage 22 as well as in the control of the heatingand discharge of the casting ma- That is to say, in charging a cylinderwith two or more successive charges intermediate each injection strokefor injecting the casting material from a cylinder or nozzle into themold cavity of a die.

In forming the cas-t body I4 it will be apparent that a gate Illa willbe formed thereon by virtue of the passage 22. This gate is arrangedcentrally of the body I4 and is removed in the operation of cutting orsevering the body III v are arranged and guided between the relativelymovable dies l) and il. The dies ED and ll will be moved into firmengagement with the tapes, the core pins i8 will be arranged between thedie parts with the ends protruding into the impression i3, and thenozzle 23 will be then brought into registering position with thepassage 2E. Then the heatedvcasting material will be injected into theimpression i3 of the dies to form the resulting cast body ifi. in thisconnection it will be understood that the dies will be cooled in theusual or any desired manner.

The dies l and li may be separated and operated in any desired mannerand it is preferred that the die IB be arranged in a yoke-shaped orother frame, parts of which are shown at 24, so l as to provideclearance for the gooseneck or discharge nozzle 23. it will also beunderstood that the discharge nozzle or gooseneck may be movedtransversely with respect to the die ill as seen at 23a in Fig. 6 of thedrawing to maintain the discharge of the nozzle sealed against thesurface of the die which is especially desirable in castingthermoplastics. In other words, with this construction, the nozzle willalways be maintained in juxtaposition to the die and will be movablewith it and relatively to it in opening and closing the dies andintermittent the injection charges of casting material into the moldcavity of the dies. It will of course be understood that our inventionis not limited to any particular size or contour of the dual linksformed, nor to any particuiar shape or contour of the projections 2Q,2da and recesses i9, lila on opposed surfaces of the pair of linksproduced in the single casting operation as above described.

In completing the formation of the two stringers, the dual unit seen inFig. 4 is fed between two jawsor guides 25a arranged adjacent a disk sawor cutter This cutter may be moved toward and from the jaws 25, 25a orthe latter moved toward and from the cutter 25 whichever may be desired,so as to sever the links l5, |5a one from the other as indicated at 21in Fig. 5 of the drawing; thus forming the separate fastener stringerswhich may be then coupled one with the other as in other devices of thiskind. In the severing or splitting operation illustrateddiagrammatically in Fig. 5, it will be understood that this may beaccomplished by a single cutter or by a series of cutters. 'it will alsoappear that the stringer tapes may be moved longitudinally of the guideand supporting jaws 25, 25a or these jaws may constitute part of theconveyor for conveying the dual links to be severed across or beneathone or more of the cutters or saws 2S, as will be apparent.

In the use of' some materials in forming the dual casting it may benecessary and desirable to trim the outer edges of the resulting linksto finish the same. This may be done in accordance with conventionalmethods of trimming or buiiing articles of the character described. Itwill also be understood that the gates ida, of the resulting castingsmay be trimmed oi prior to the severing operation such as illustrated inFig. 5 of the drawing, or these gates may be removed in the -Latteroperation.

In Fig. 4 ofthe drawing we have indicated at 2G, 28o, two strands whichare arranged longitudinally of the tapes It, ita or the enlarged beadededges E?, 'la thereof. These strands may either constitute rayon threadsstitched or otherwise applied to the beaded edges, or the strands may bein the form of wire strands correspondingly arranged so as to contacteach of the links on the separate stringers. Rayon is used whenthermoplastic castings are employed, and metallic strands when the metalcastings are employed. The rayon threads facilitate a more secureanchorage of the links to the tapes especially in treating the tapeswith an acetone or other solution which acts as a solvent both for thelinks and the rayon thread and provides a secure mounting of the linksto the Stringer tapes. On the other hand, the metallic strands which areemployed in conjunction with the metal castings facilitateelectroplating of the resulting castings, which operation will beperformed after the links have been severed as taught in Fig. 5 of thedrawing.

It will be understood that in casting diierent forms and types of linksof the character described and especially in forming smaller links,weakened lines of parting may be provided between the adjacent pair oflinks to permit easy severing thereof. This will also be true in castingpairs of other types and kinds` of devices in accordance with theteachings herein shown and described, regardless of the type and kind ofmounting member employed, or in fact, regardless of the use of any suchmounting member. It is understood in this connection that four core pinscould be used instead of the two shown. the latter core pins being ofthe cross sectional contour of the tapes employed. The result of thismethod of procedure would be the formation of a pair of links having thechanneled ends adapting them for mounting on Stringer tapes.

From the foregoing it will appear that one of the distinctive featuresof the invention resides in the use or" a single impression die Soconstructed as to form simultaneously a pair of two similar die castdevices which are joined in the unitary casting and then later severedto form two similar or substantially similar parts.

Having fully described our invention, what we claim as new and desire tosecure by Letters Patent, is:

l. The herein described method of forming a f pair of complete stringersof separable fasteners of the character described, which consistsinproviding a pair of dies movable toward and from each other, providing asingle cavity between adjacent surfaces of the dies of a contourdefining the peripheral contour of a pair of links arranged in endwiserelationship, arranging two separate stringer tapes between adjacentsurfaces of the dies, each extending into the cavity of the dies from,opposite sides thereof and terminating in spaced relationship to eachother within the cavity, arranging a pair of core elements between thedies with part thereof extending into said cavity to form a recess ineach o the resulting pair of links, injecting casting material underpressure into the cavity of the dies and around said tapes and coreelements to form a unitary die cast body joining both of said stringers,then removing said body from the dies and core elements and severingsaid body centrally to form independent links arranged upon independentStringer tapes.

2. The herein described method of forming a pair of complete stringersof separable fasteners of the character described, which consists inproviding a pair of dies movable toward and from each other, providing asingle cavity between adjacent surfaces of the dies of a contourdefining the peripheral contour of a pair of links arranged 'in endwiserelationship, arranging two separate Stringer tapes between adjacentsurfaces of the dies, each extending into the cavity of the dies fromopposite sides thereof and te niinating in spaced relationship to eachother Within the cavity, arranging a pair of core elements between thedies with part thereof extending into said cavity to form a recess ineach of the resulting pair of links, injecting casting material underpressure into the cavity of the dies and around said tapes and coreelements to form a unitary die cast body joining both of said stringere,then removing said body from the/dies and core elements and severingsaid body centrally to form independent links arranged upon independentStringer tapes, and treating the Stringer tapes to aid in securing eachof the links thereon.

3. The herein described method of forming a pair of complete stringereof separable fasteners of the character described, which consists inproviding a pair of dies movable toward and from each other, providing asingle cavity between adjacent surfaces or" the dies of a contour deningthe peripheral contour of a pair or" links arranged in endwiserelationship, arranging two separate stringed tapes betwen'adjacentsurfaces of the dies, each extending into the cavity of the dies fromopposite sides thereof and terminating in spaced relationship to each`other' Within the cavity and each tape having a rayon thread in theportion thereof disposed Within the cavity and extending longitudinallyof the tape, arranging a pair of core elements between the dies withpart thereof extending into said cavity to form a recess in each of theresulting pair of links, injecting casting material under pressure intothe cavity of the dies and around said tapes and core elements to form aunitary die cast body joining both of said stringers, then removing saidbody from the dies and core elements and severing said body centrally toform independent links arranged upon independent Stringer tapes.

4. The herein described method of forming die castings of the characterdescribed, which` consists in arranging portions of two spaced mountingstrands between adjacent surfaces of relatively movable dies having asingle cavity therein with said portions of the strands arranged in saidcavity in spaced relation to each other, pressure feeding castingmaterial into said cavity of the dies While holding said dies in firmengagement with each other to form a unitary cast body in said cavityand upon that part of the strands arranged in the cavities andintermediate said strands, then removing the casting from the dies, andthen severing theA unitary cast body intermediate said strands to formindependent castings one arranged upon each of said strands.

LOUS H. MORIN. DAVIS MARINSKY.

